This adds a function engine.FuncMap that returns a function mapping that
better represents the functions passed to a template. The linting logic
is reconfigured to use this function instead of the sprig.FuncMap
function.

Closes #1366

The YAML validation was broken because the renderedContentMap has keys
with the path to the template including the chart directory, whereas the
linter was trying to access it relative from the chart directory.

For example, the hash key was `drupal/templates/deployment.yaml` but the
linter was trying to access `templates/deployment.yaml`. This commit
fixes the key used to access the rendered content.

Fixes the regex for extracting templates to include templates that
suppress newlines and ignore any conditional flow statements.

This removes the last of the requests for gopkg.in/yaml.v2, and
also the struct annotations.

Closes #1192
Closes #1263

closes #1161

https://golang.org/doc/go1.4#canonicalimports

Handle a previously unhandled error in the linter. This simply bails out
if a chart's values files do not parse.

Also, changed the implementation of CoalesceValues to return a map even
on error.

Closes #847.

Fixing unit test

Template rules

Adding chart errors

Added function that checks the existence of all the values in the templates

Adding chartfile unit tests

Testing runLinterRule

Fixing out of range

Fixing out of range

Improving quote detector

Fixed tests

Adding chart name linter

Add lint error

Moving to blocks

Moving to method

Moved lint rules to functions

Semantic version validation

Linting engine

Adding sources and home validations

Sharing file loading

Sharing file loading

Rolling back readme

Rewriting other linters

Fixing tests

Typo

Using chart.Metadata

Fixing format

Adding UNKNOWN in Engine

Adding tabs

Fixing tabs